JPS6024656B2 - Maximum demand power monitoring control method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION In a power system equipped with private power generation equipment, the present invention is capable of controlling the output of the private power generation equipment or selecting the load of process equipment so that the amount of power used by the power receiving system is equal to or less than the specified amount of power. The present invention relates to a maximum demand power monitoring and control method that performs power cut-off control and automatically reinserts the shrunken load so that the amount of power reaches a specified value after the shear-shut control.

Conventionally, maximum power demand control in power receiving and substation equipment has been used to select load selection when the amount of power used by the power receiving system is expected to exceed the specified amount of power, based on a predetermined priority order for process equipment connected to the power grid. A method of cutting is used.

Additionally, customers with private power generation equipment control the maximum power demand by controlling generator output in order to make effective use of the private power generation equipment. However, in recent years, there has been an increase in the number of customers who are equipped with in-house power generation equipment, even for small-scale power receiving and substation facilities, for use in emergencies during power outages.

Even in customers equipped with private power generation equipment, maximum demand power is controlled by load selection and disconnection methods without using private power generation equipment. Therefore, in order to judge the load in use, accurately predict the amount of power used in the power system, and select the necessary load within a range that does not exceed the specified amount of power, the only way to do so is to rely on intuition based on conventional operating experience. Similarly, after a load has been temporarily disconnected, the task of reinserting the disconnected load due to an increase in the amount of power in the power system has been based only on intuition based on operating experience. It has been desired to comprehensively judge these factors and to perform accurate load control and load application control, but this has hardly been considered in the past. The present invention accurately predicts the scheduled amount of power to be used in a power receiving system equipped with in-house power generation equipment, effectively utilizes the in-house power generation equipment, and performs accurate load selection, disconnection, and automatic restart control to achieve the specified amount of power. The purpose of the present invention is to provide a maximum demand power monitoring and control method that enables maximum load usage without exceeding the maximum demand.

An embodiment of the present invention will be described below with reference to the drawings. 1st
The figure shows an example of a power system equipped with private power generation equipment to which the present invention is applied. In Fig. 1, 1' is a disconnector, 2 is a disconnector, 3 is a power meter for transaction, 4 is a transformer, and 5 is a load.
6 is a private generator. Electric power is supplied to the load 5 in parallel from a power transmission system and a private generator 6. FIG. 2 is a configuration diagram of an example of a system to which the present invention is applied, and the electric energy input to the trading electric energy meter 3 is measured by the arithmetic and control unit (
(hereinafter referred to as CPU) 7. The CPU 7 calculates the alarm over limit value as shown in FIG. 3 based on the value set by the setting device 8, and outputs an alarm message chime to the CRT display device 9 when the amount of power used is an alarm. If the amount of power is over, an over message chime is output to the CRT display device 3. If the predicted power consumption exceeds the target power consumption, controller 10
is used to control the output of the generator 6, and when the output of the generator is higher than the rated value, a cut-off/turn-on command is sent to the process equipment 5 of the corresponding load. 3 is an electric energy meter for transaction.

Next, the operation of the present invention will be explained using FIGS. 3 and 4. From the set target value MS set by the setter 8, the contract time TS minutes, and the elapsed time T minutes, the target over-limit upper limit MT and target alarm upper limit ST for the elapsed time T minutes are calculated (steps 14, 15). That is, MT=(Ms−M
L)X house fML.・-． ...'11 However, MS is the target value at the end of monitoring, M mountain is the over target value at the start of monitoring, T is the elapsed time, and TS is the contract time.

sT=(ss-sL)X poisonous skin....・．． ．． ...[21
However, SS is the target value at the end of monitoring, and SL is the alarm target value at the start of monitoring.

As shown in Fig. 4, the alarm target values ML and SL are set to certain values at the start of monitoring when the demand monitoring is performed while the elapsed time of demand monitoring is small (e.g., elapsed time of 3 minutes). This is to avoid issuing too many alarms when the demand elapsed time is short, since even if an alarm sounds, it has little effect on demand over.

Next, the electric energy input into the transaction electric energy meter 3 is integrated for each unit time, and the electric energy used in the elapsed time T minutes is calculated as MP.
Then, the power consumption MP is calculated (step 16).

That is, M Yen = MC x MJ However, MC is the number of pulse inputs accumulated per unit time, MJ
is the multiplier per pulse.

Next, the amount of electricity used in the elapsed time T minutes MQ and (T-1)
The predicted amount of power consumption YS at the end of monitoring is calculated from the average instantaneous power ΔM from minute to T minutes and the remaining time (TS-T) until the end of monitoring (step 17).

That is, YS=MP+△M×(TS-T).・．．・
．． ．． ■Next, the target alarm upper limit value ST and the power consumption MP are compared (step 18), and if the power consumption M yen exceeds the target alarm upper limit value ST, the CRT display device 9
An alarm message is issued (step 19) to notify the user of a minor abnormality.

Furthermore, the target excess upper limit value MT and the power consumption MP are compared (step 20), and when the power consumption M yen exceeds the target excess upper limit value MT, an over message is displayed on the CRT display device 9 (step 21), and a serious error is detected. Inform the user of the status. Furthermore, the target value MS at the end of monitoring
and the predicted power consumption YS (step 22), and if the predicted power consumption YS exceeds the target value MS at the end of monitoring, it is compared to see if it is a controllable time period (step 23).
Furthermore, the amount of power used M yen is compared with an upper limit value DT that is parallel to the target alarm upper limit value (step 24), and the magnitude of the load fluctuation is determined. The upper limit value DT is determined as follows. DT=
MS 蓑MLxT+A However, A is a value of a certain ratio to the target value (Mount M) at the start of monitoring of the target over-upper limit value.

If it is determined that the load fluctuation is not large (DT - MP), the process proceeds to step 25, and optimal control is performed by controlling the output of the generator so that the power consumption MP reaches the target value MS at the end of monitoring within the contract time. Let's do it. If the generator output has reached the rated output and cannot be controlled by the generator output any further (
In step 26), the process proceeds to steps 27 and 28, and optimal control is performed by load selection and cutoff control. One monitoring control from step 14 to step 28 described above is performed by subdividing one monitoring cycle time period TS, for example, every minute. Next, when entering the monitoring cycle time period TS, the predicted power consumption YS exceeds the target upper limit value MT'
If it is smaller than the line ZT that is parallel to this and passes through the power consumption M circle (
In step 29), load selection is automatically performed by the target value ZS at the end of monitoring minus the predicted power consumption YS, and the load is automatically turned on again according to the priority order of shutdown (step 30).

Here, the optimum control method is performed by reducing the power consumption MP used by the process equipment 5 through a combination of generator output control and load selection/off control.

Below, the process equipment 5 is electric motor M1, M2, M3, M4,
A case where five M5 units are controlled will be explained. The process equipment 5 can easily set the load amount and change the priority order via the CPU 7 using the setting device 8.
It is assumed that the PU 7 controls the amount of power input to the transaction power amount measuring device 3 using the private generator 6 . If the predicted power amount YS exceeds the target value MS at the end of monitoring, control will not be performed if the elapsed time is less than TS/2 minutes, and if the elapsed time is more than TS/2 minutes, control will be performed to the private generator 6 through the controller 10. (YS-MS)/Tobi; is output.

The amount of electricity used by the ship's power shelf 5 is supplied by the private generator 6 (YS-MS), and the amount of electricity input to the transaction electricity measuring device 3 is the same amount as the above amount. As a result, the increase in instantaneous power ΔM becomes smaller in the next cycle.

Furthermore, after the unit time has elapsed, the predicted power amount YS is compared with the target value MS at the end of monitoring, and if the predicted power amount YS further exceeds the target value MS, it is compared whether the generator output is at the rated value, When the generator output is at the rated value, the next load selection and cutoff control is performed as follows. Determine the power shortage in the generator output from the difference between the predicted power usage YS and the generator surplus power, select the process equipment 5 based on the priority of the process equipment 5, and adjust the total power value of the process equipment to the target value MS. A selective cutoff command is output to the process equipment 5. By combining generator output control, load selection and cutoff control, it is possible to optimally control a load group without exceeding the specified amount of power. Furthermore, in the next monitoring cycle, if a load can be applied due to a decrease in the amount of power used in the power receiving system, etc., the following control is performed. Elapsed time T
is 15 minutes or more, and if it is 18 minutes or more, the value ZS at the end of monitoring is determined from a line ZT' that is parallel to the target excess upper limit value passing through the current power consumption. Furthermore, due to the difference from the predicted power consumption YS, the following power amount PS
The load is automatically re-injected based on the load selection priority order. Re-inputable power towers are determined as follows. I = (public - YS) x blue et al. However, public is the target value at the time of TS on the line parallel to MT passing through the current amount of electricity used.

As described above, according to the present invention, it is possible to use the load to the maximum without exceeding the specified amount of electric power, and the operator can perform load switching, turning on, and turning on the load, which had previously relied on the operator's intuition. It is possible to reduce the burden on the operator, operate accurately and quickly, and also perform efficient optimal load control through generator output control, load selection/off control, and load selection/on-on control. A power monitoring control method can be provided.

[Brief explanation of the drawing]

Figure 1 is a power system diagram to which the present invention is applied, Figures 2 to 4 are for explaining embodiments of the present invention, Figure 2 is a configuration diagram of a system to which the present invention is applied, and Figure 3 is A flowchart explaining the present invention, and FIG. 4 is a curve diagram explaining the relationship between the set target value and the amount of power used in the present invention. 3...Energy meter for transaction, 5...Process equipment, 6...Private generator, 7...
... Arithmetic control unit, 8 ... Setting device, 9 ...
・・CRT display device, 10・・・・Controller, MQ・
...Energy consumption, YS...Estimated power consumption,
MT...Target over upper limit, ST...
- Eye collar alarm upper limit value, MS: Over target value at the end of monitoring, SS: Alarm target value at the end of monitoring. Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] 1 The set target value MS at the end of the demand cycle TS,
From the set target value ML at the start of the demand cycle TS,
The target excess upper limit MT for each elapsed time T is expressed as MT=(MS
-ML)×T/(TS)+ML is calculated, and the amount of power used M in the elapsed time T_1 from the start of the demand cycle TS to the present for each fixed monitoring cycle within the demand cycle TS
P, calculate the predicted power consumption YS at the end of the demand cycle TS from the average instantaneous power at the current point and the remaining time, and if this predicted power consumption YS is greater than the target set value MS, calculate the elapsed time up to the present time. Determine whether T_1 is greater than or equal to the set value, and if so, determine whether the current power consumption MP is greater than the upper limit value DT for load fluctuation determination, which is set a certain value lower than the target over-upper limit value at this time; If it is larger, the private power generation output that is operated in parallel is controlled based on the difference between the set target value MS and the predicted power consumption YS, and the demand cycle following the demand cycle TS in which the private power generation output was controlled is performed. Then, it is determined whether the elapsed time T_2 within this period TS is equal to or longer than the set time, and if it is, the elapsed time T_2 is determined.
Calculate the target value ZS at the end of the demand period TS at a rate of increase equal to the rate of increase of the target over-upper limit value MT for each elapsed time T based on the power consumption MP at _2, and
A maximum demand power monitoring and control method that compares the predicted power consumption YS at the end of the demand cycle TS predicted at the elapsed time T_2, and if ZS>YS, loads a capacity corresponding to the difference between them.